Question: Add.
Answer: There are many ways to solve this problem. Let's see two ways we can solve it. Place value table Let's line up the numbers by their decimal places. Tens Ones $.$ Tenths $6$ ${4}$ $.$ ${0}$ $5$ $.$ ${6}$ Because ${64}$ is a whole number, we can add a decimal point and a $0$ behind to make the columns align. Now, let's add each place value column. Tens Ones $.$ Tenths $6$ ${4}$ $.$ ${0}$ $+$ ${5}$ $.$ ${6}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $\underline{~~~~}$ $6$ $9$ $.$ $6$ Decomposing the numbers We can group the whole numbers together and the decimals together. $\begin{aligned} &({64} + {5}) + {0.6}\\\\ &=69 + {0.6}\\\\ &=69.6 \end{aligned}$ $69.6 = 64 + 5.6$